Water pump control device

Abstract

To provide a water pump control device capable of suitably setting a threshold used for determining abnormality of a water pump, according to an average rotating speed in normal operation corresponding to a use state of the water pump.SOLUTION: A water pump control device mounted on a vehicle, comprises: a storage part which calculates and stores an average rotating speed of a water pump in a present trip for each control value for driving the water pump; a determination part which determines whether or not each average rotating speed stored in the storage part exceeds a predetermined threshold set according to the control value; and an update part which updates the threshold used by the determination part in a next trip with the average rotating speed stored in the storage part by the present trip when the determination part determines that there is an average rotating speed exceeding the threshold during the present trip.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a water pump control device. [Background technology]

[0002] Patent Document 1 discloses a vehicle cooling system that can cool devices mounted on a vehicle using the operation of a water pump. The vehicle cooling system in Patent Document 1 describes a method for determining that an abnormality has occurred in the water pump when the rotation speed of the water pump exceeds a predetermined value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-066279 Summary of the Invention [Problem to be solved by the invention]

[0004] The rotational speed of a water pump varies depending on its usage. Therefore, if the rotational speed (threshold) for determining whether or not there is an abnormality is set uniformly without taking into account the usage status of the water pump, there is a risk that the water pump will be determined to be abnormal even when it is operating normally.

[0005] Therefore, there is room for further consideration regarding the method of setting the threshold value used to determine whether the water pump has an abnormality.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a water pump control device that can appropriately set the threshold value used to determine abnormalities in a water pump according to the average rotation speed during normal operation, which is in accordance with the usage status of the water pump. [Means for solving the problem]

[0007] In order to solve the above problem, one aspect of the disclosed technology is a water pump control device mounted on a vehicle, which includes: a memory unit that calculates and stores the average rotation speed of the water pump in the current trip for each control value that drives the water pump; a judgment unit that determines whether each of the average rotation speeds stored in the memory unit exceeds a predetermined threshold value set in accordance with the control value; and an update unit that, if the judgment unit determines that an average rotation speed during the current trip has exceeded the threshold value, updates the threshold value used by the judgment unit in the next trip with the average rotation speed stored in the memory unit for the current trip. [Effects of the Invention]

[0008] According to the water pump control device disclosed above, a threshold value used to determine whether the water pump is abnormal is set based on the average rotation speed of the water pump for each control value, so that the threshold value can be appropriately set according to the average rotation speed during normal operation depending on the usage status of the water pump. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a functional block diagram showing a schematic configuration of a water pump control device and a cooling system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram showing an example of the average rotation speed of a water pump stored in a storage unit; [Figure 3] A process flowchart of high speed determination control executed by the water pump control device DETAILED DESCRIPTION OF THE INVENTION

[0010] For example, to protect the inverter elements from overheating, it is conceivable to determine whether the water pump is in a high rotational speed state (due to cooling water leakage or air entrapment) and raise the estimated element temperature. However, if the threshold value for determining high rotational speed, which indicates an abnormal state of the water pump, is a fixed value, there is a risk that the system may erroneously determine that the rotational speed is high abnormally when the normal rotational speed increases due to factors such as wear on the bearings of the motor that rotates the water pump impeller.

[0011] In the water pump control device disclosed herein, in order to avoid such erroneous judgments, the threshold value for judging high rotation abnormalities is updated to the average value of the water pump rotation speed during an actual trip, thereby responding to increases in rotation speed that are not due to coolant leakage and improving the accuracy of high rotation judgments. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0012] <Embodiment> [composition] FIG. 1 is a functional block diagram showing a schematic configuration of a water pump control device 100 and a cooling system 200 controlled by the water pump control device 100 according to an embodiment of the present disclosure.

[0013] The water pump control device 100 and the cooling system 200 are mounted on, for example, a vehicle, etc. Hereinafter, an embodiment will be described taking as an example a case where the water pump control device 100 and the cooling system 200 are mounted on a vehicle.

[0014] The cooling system 200 includes a water pump (W / P) 210, a power control unit (PCU) 220, an oil cooler (O / C) 230, a radiator 240, and a reserve tank 250. These components are connected to each other by cooling pipes 260 for circulating and supplying cooling water.

[0015] The water pump 210 is a unit for circulating the cooling water (or coolant) inside the cooling pipes 260. The power control unit 220 is a unit that includes an inverter that drives the driving motor, a DC-DC converter that converts voltage, and the like (not shown), and controls the power supplied to the driving motor. The oil cooler 230 is a unit that cools the drive train (not shown), including the driving motor, and the like, by using oil circulating inside the oil cooling pipes. The radiator 240 is a unit that cools the cooling water by using air. The reserve tank 250 is a unit that stores the cooling water. The power control unit 220 and the oil cooler 230 are objects that are cooled by the cooling water circulating through the cooling pipes 260.

[0016] The water pump 210 includes a motor for rotating an impeller inside a pipe and a control circuit (not shown) for PWM (Pulse Width Modulation) control of the motor's operation. The rotation speed of the impeller, i.e., the rotation speed of the water pump 210, can be changed by controlling the ON / OFF ratio (hereinafter referred to as "duty") of the PWM signal, which is a control value for driving the motor. Specifically, increasing the duty (control value) increases the motor's rotation speed, and decreasing the duty (control value) decreases the motor's rotation speed. The cooling performance of the cooling system 200 changes in proportion to the rotation speed of the water pump 210. This duty control is performed based on a predetermined command given by an electronic control unit (ECU).

[0017] Water pump control device 100 is configured to control water pump 210, and more specifically has a function to determine abnormalities such as high rotation speed of water pump 210. Water pump control device 100 includes a storage unit 110, a determination unit 120, and an update unit 130.

[0018] Storage unit 110 calculates and stores the average rotation speed of water pump 210 during a "trip," which is the period from when the vehicle starts to run until when it finishes running. More specifically, while the current trip (current trip) is ongoing, storage unit 110 calculates the average rotation speed of water pump 210 every time it is driven, for each predetermined duty of the PWM signal that drives water pump 210, and rewrites and stores the calculated value each time. Storage unit 110 is capable of monitoring the duty of the PWM signal that is issued to water pump 210.

[0019] FIG. 2 shows an example of the average rotation speed of the water pump 210 stored in the storage unit 110. In the example shown in FIG. 2, the average rotation speed during the period when the water pump 210 is driven at a duty of 50% (50% driven, 50% stopped) is 3180 rpm, the average rotation speed during the period when the water pump 210 is driven at a duty of 52% (52% driven, 48% stopped) is 3426 rpm, the average rotation speed during the period when the water pump 210 is driven at a duty of 58% (58% driven, 42% stopped) is 3389 rpm, and the average rotation speed during the period when the water pump 210 is driven at a duty of 64% (64% driven, 36% stopped) is 4455 rpm. These values ​​are provisional values ​​at that time. If the water pump 210 is driven again at the same duty before the end of the trip, the duty average rotation speed is updated as needed. Furthermore, if the water pump 210 is driven at a new duty, an item for the new duty is added as needed.

[0020] Determination unit 120 determines whether water pump 210 has entered a high rotation speed state. Specifically, determination unit 120 determines whether the average rotation speed of water pump 210 for each duty stored in memory unit 110 has exceeded a predetermined threshold value (hereinafter referred to as a "high rotation speed determination threshold value") set according to the duty. The rotation speed of water pump 210 can be obtained using a rotation speed sensor (not shown) that detects the rotation speed of the motor.

[0021] Update unit 130 updates the high-speed determination threshold used by determination unit 120 in the next trip (next trip) as necessary. Specifically, when determination unit 120 determines that the average rotation speed of water pump 210 exceeded the corresponding high-speed determination threshold for at least one duty during the current trip, update unit 130 updates the high-speed determination threshold used by determination unit 120 in the next trip with the average rotation speed of water pump 210 stored in storage unit 110 after the end of the current trip. This update may be performed for all duties, or may be performed only for duties for which the average rotation speed exceeded the high-speed determination threshold.

[0022] [control] Next, the control performed by the water pump control device 100 according to an embodiment of the present disclosure will be described with further reference to Figure 3. Figure 3 is a flowchart illustrating the processing procedure of the high rotation speed determination control executed by each component of the water pump control device 100.

[0023] The high speed rotation determination control shown in FIG. 3 is started, for example, when a trip of the vehicle begins, and is repeatedly executed until the trip ends.

[0024] (Step S301) The determination unit 120 determines whether the water pump (W / P) 210 is operating. This determination is made based on the duty of the PWM signal that drives the water pump 210. More specifically, if the rate at which the water pump 210 is driven is greater than the rate at which the water pump 210 is stopped (W / P drive duty > W / P stop duty), the water pump 210 is determined to be operating. If the water pump 210 is operating (step S301, Yes), the process proceeds to step S302. On the other hand, if the water pump 210 is not operating (step S301, No), the process waits until the water pump 210 starts operating.

[0025] (Step S302) The storage unit 110 calculates and stores the average rotation speed of the water pump 210 for each duty of the PWM signal that drives the water pump (W / P) 210. The method of calculating and storing the average rotation speed is as described above. Once the average rotation speed of the W / P is stored in the storage unit 110, the process proceeds to step S303.

[0026] (Step S303) The determination unit 120 determines whether any of the average rotation speeds of the water pump (W / P) 210 for each duty stored in the storage unit 110 exceeds a high rotation speed determination threshold set for that duty. In other words, the determination unit 120 determines whether a "W / P high rotation speed abnormality" has occurred, in which the average rotation speed of the W / P with a duty of X% (X = 50 to 100) exceeds the high rotation speed determination threshold set for the duty of X%. If any of the average rotation speeds of the W / P exceeds the high rotation speed determination threshold (Yes in step S303), the process proceeds to step S304. On the other hand, if any of the average rotation speeds of the W / P does not exceed the high rotation speed determination threshold (No in step S303), the process proceeds to step S305.

[0027] (Step S304) The update unit 130 maintains the current high-speed determination threshold set for each duty without updating it. The reason for this is that if it is determined that the average rotation speed of the water pump 210 has exceeded the high-speed determination threshold even once during the current trip, it means that the average rotation speed during normal operation has not been accurately calculated. Therefore, in this case, it is determined not to update the high-speed determination threshold. If the update unit 130 maintains the high-speed determination threshold, the process proceeds to step S301.

[0028] (Step S305) The update unit 130 updates (rewrites) the current high-speed determination threshold set for each duty with the average rotation speed of the water pump (W / P) 210 for each duty stored in the storage unit 110. By updating the high-speed determination threshold in this manner, it becomes possible to respond to a non-abnormal increase in the rotation speed of the water pump 210 caused by, for example, wear on the motor bearings of the water pump 210, during the abnormality determination process for the next trip. Once the high-speed determination threshold has been updated by the update unit 130 with the average rotation speed of the W / P, the process proceeds to step S301.

[0029] <Actions and Effects> As described above, according to the water pump control device 100 of one embodiment of the present disclosure, by comparing the average rotation speed calculated from the water pump rotation speed that can be obtained under normal conditions with the high rotation speed judgment threshold, it is possible to determine whether cooling performance has decreased due to loss of coolant, and to protect the element from overheating by raising the estimated element temperature.

[0030] In other words, according to the water pump control device 100 of this embodiment, the average value of the water pump rotation speed is calculated and stored for each trip, and the high rotation speed judgment threshold is updated to that average value, thereby making it possible to respond to increases in the water pump rotation speed that are not due to coolant leakage, such as wear on the motor bearings inside the water pump, and improving the accuracy of high rotation speed judgment. [Industrial Applicability]

[0031] The water pump control device of the present disclosure can be used in vehicles equipped with a cooling system that uses a water pump. [Explanation of symbols]

[0032] 100 Water pump control device 110 Storage section 120 Judgment section 130 Update Department 200 Cooling System 210 Water pump (W / P) 220 Power Control Unit (PCU) 230 Oil cooler (O / C) 230 240 Radiator 250 reserve tank 260 Cooling Pipe

Claims

[Claim 1] A water pump control device mounted on a vehicle, a storage unit that calculates and stores an average rotation speed of the water pump for each control value that drives the water pump during a current trip; a determination unit that determines whether or not each of the average rotation speeds stored in the storage unit exceeds a predetermined threshold value that is set in accordance with the control value; an updating unit that, when the determining unit determines that the average rotation speed exceeds the threshold value during the current trip, updates the threshold value used by the determining unit in the next trip with the average rotation speed stored in the storage unit during the current trip, Water pump control device.

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